There has been an on-going effort to more efficiently capture the heat generated by fireplace fires and to so direct that heat to raise the temperature of living quarters rather than permitting such heat to escape through the chimney. In a conventional fireplace heat is generated to the living quarters primarily by radiation only, approximately 90 to 95 percent of its heating capacity being lost to the outside atmosphere. Thus, a device which can effectively capture and circulate into a room, such as by convection, some of this waste heat would be extremely beneficial and, in fact, previous attempts at developing such a device have been made.
In particular, Englert U.S. Pat. No. 3,635,211 shows a heat exchanger with grate and air transporting pipes located below the fuel media leading to triangular fins above the fuel media. A blowing means is used to assist movement of air through the system. Hatfield et al. U.S. Pat. No. 3,905,351 shows a heat distribution unit with heating conduit in a V-shaped version and a manifold located at the front of the device. A blower is provided adjacent to the manifold.
In Maasberg U.S. Pat. No. 3,269,385 a manifold is located at the rear and contains a blower within its interior. The log supporting elements are tubular and are provided with air outlets along their length. In Schutt U.S. Pat. No. 3,240,206 the manifold is tubular and located in the rear connecting the blower and log supporting element. A means is also provided for feeding oxygen to the fire. The Stites U.S. Pat. No. 2,901,212 shows a U-shaped heating conduit wherein the lower portion of the conduit supports the logs. The device is equipped with a manifold and blower at the bottom front end with the blower located outside the fireplace.
Each of the above units entail the passing of forced air through conduits or a system of conduits, which conduits are heated by the fireplace fire, thereby heating the air passing therethrough, such heated air being directed into the room. These prior units are, however, believed to be lacking in one or more important characteristics, for example: simplicity and therefore economy of construction, efficiency of heat transfer from the core of the fire in terms of output per unit of fuel burned, ready adaptability to size of fireplace, attractive rather than detractive appearance, portability with ease.